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Iam trying to make an easy way of defining my IO. Im trying to do this with macro but I cant solve this problem.

I did this:

// Buzzer PORT and PIN mapping
#define BUZZER_PORT     B       // PORT
#define BUZZER_PIN      2       // PCR pin
#define BUZZER_ALT      1       // Pin alternativne function

#define INIT_BUZZER(PORTX, PIN, ALT) { PORT##PORTX##_PCR(PIN) = PORT_PCR_MUX((ALT)) |     PORT_PCR_DSE_MASK;            GPIO##PORTX##_PDDR |= PIN<<1; }

Function call working:

INIT_BUZZER(B, BUZZER_PIN, BUZZER_ALT);

Function call wanted:

INIT_BUZZER(BUZZER_PORT, BUZZER_PIN, BUZZER_ALT);

If I call it with port argument BUZZER_PORT I get an error because compiler doesnt take my arguments value but string itself.

How to deal with this?

Thank you.

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2 Answers

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use brackets as most as possible.

try below： INIT_BUZZER((BUZZER_PORT), BUZZER_PIN, BUZZER_ALT);

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up vote 0 down vote

You need an indirection:

#define INIT_BUZZER_(PORTX, PIN, ALT)                                   \
    do {                                                                \
        PORT##PORTX##_PCR(PIN) = PORT_PCR_MUX(ALT) | PORT_PCR_DSE_MASK; \
        GPIO##PORTX##_PDDR |= (PIN)<<1;                                 \
    } while (0)

#define INIT_BUZZER(PORTX, PIN, ALT)                                    \
        INIT_BUZZER_(PORTX, PIN, ALT)

Also note the do {...} while(0) and no semi-colon, which is the normal way to enclose several lines in a macro

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Thank you. In that situation it works. What if I want to define a macro of toggle pin without argument something like this: – user2566355 Jul 10 at 8:02
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